Biography: Sarah Margaret Hagan (born May 24, 1984 in Austin, Texas) is an American television and movie actress. She has been acting since the age of six, when her mother first signed her up for musical theater.

Hagan was first involved with theater companies such as Houston's Playhouse 1960, the Houston Grand Opera (where she sang in the children's chorus), the Crighton Playhouse, the Houston Music Hall and the Bitter Truth Theater. From there, she made her screen debut in the 1997 feature film Faith, where she played the title character at age 13; her TV debut came on an episode of the Calista Flockhart series Ally McBeal in 1999.

Hagan's first major break came when she was cast in a recurring role as Millie Kentner on the short-lived NBC cult TV series Freaks and Geeks (1999-2000). Following that show's cancellation, she was cast in the David Alan Grier NBC sitcom DAG, where she was originally slated to play Camilla Whitman, daughter of the US President; however, the role of Camilla was recast when the pilot episode was revamped before airing (with Lea Moreno Young taking over the role; Hagan was put in the credits in a guest role, but did not appear in the episode).

The next movie role for Hagan was in a bit part in the Jack Black feature Orange County in 2002. After that, she was cast as Amanda in the seventh and final season of the hit cult series Buffy the Vampire Slayer.

She recently appeared on the ABC medical drama Grey's Anatomy as Devo, a teenage girl whose religious beliefs conflict with getting treatment for a heart condition she was diagnosed with; and she is currently filming the teen comedy/drama feature Odd Girl Out with Buffy castmate Michelle Trachtenberg.